VERMICULARIA. 471 



Vermicularia trichella Fr. occurs ou living leaves of ivy and other plants. 

 (Britain.) 



V. ipomoearum Schw. On species of Ipomoea in America. 



V. microchaeta Pasc. On living leaves of Oa'>nellia japonica in Italy. 



V. circinans Berk. Onion rot in Britain and U.S. America. 



Placosphaeria and Cytospora are genera containing forms 

 parasitic on living plants, but of little practical importance. 



Phaeosporae. 

 Goniothyrium. 



Pycnidia brown or black. Conidia brown, unicellular, spheroid 

 or ovoid, and borne on short conidiophores. 



Ooniothyrium (Phoma) diplodiella Sacc.^ White-rot of the 

 vine. This disease has a wide distribution in Hungary, and has 

 also been observed in France, Italy, and America. It has caused 

 considerable damage, especially in Northern Italy, where it was 

 for a long time regarded as the black-rot. 



According to Mezey, this parasite is distinguished from 

 Laestadia (black-rot) in the following points : — The pycnidia 

 and conidia are larger ; the mature pycnidia are greyish or 

 light brown (never black), the mature conidia are brownish. 

 The disease attacks the fruit only, causing it to fall off. Eathay, 

 however, states that it also attacks young shoots, infection taking 

 place from the fruit. Diseased grapes become soft, rotten, and 

 wrinkled; the ridges are beset with pycnidial pustules, as in 

 black-rot, but the grapes never become brittle and hard. 



Viala and Eavaz^ have recently succeeded in rearing perithecia 

 from twigs and fruit-stalks set in sterilized moist sand. None 

 could be found on grapes. The perithecia are globular, enclosed 

 in a black covering several cells thick, and with a large crater- 

 like aperture. The asci and paraphyses arise only from the depth 

 of the perithecium, the latter being longer than the former and 

 frequently branched. The asci are club-shaped and short-stalked, 

 and contain eight spindle-shaped colourless or yellowish asco- 

 spores, divided by one to three cross-septa. They germinate and 

 produce one or more germ-tubes. 



•Rdthay, "Der White-Rot," Die Weiidmibe, 1892. 

 General description in Report 9, New York Agric. Exper. Station, 1890. 

 ^Viala and Ravaz, Compt. rend., cxix., 1894, p. 443. 



